The billionaire investor, who scaled back his political giving after a then-unprecedented $27 million spending spree to try to defeat George Bush in 2004, has quietly reemerged as a leading funder of Democratic politics — and as a leading bogeyman of conservatives.

Soros has donated or committed more than $25 million to boost Hillary Clinton and other Democratic candidates and causes, according to Federal Election Commission records and interviews with his associates and Democratic fundraising operatives. And some of his associates say they expect Soros, who amassed a fortune estimated at $24.9 billion through risky currency trades, to give even more as Election Day nears.

The 85-year-old Hungarian-born New Yorker had planned to attend his first-ever Democratic convention here to watch Clinton, with whom he has a 25-year relationship, accept the Democratic presidential nomination on Thursday. But an associate said he decided to cancel the trip this week because Soros, who recently returned to active trading, felt he needed to closely monitor the economic situation in Europe.

Nonetheless, people close to Soros say he seems more politically engaged than he’s been in years, motivated they say by a combination of faith in Clinton and fear of her GOP rival Donald Trump, who Soros has accused of “doing the work of ISIS” by stoking fears.

Clinton and her allies have build a humming campaign machine that dwarfs Trump’s.

Soros’s political adviser Michael Vachon said his boss “has been a consistent donor to Democratic causes, but this year the political stakes are exceptionally high.” Vachon added: “They were high even before Trump became the nominee because of the hostility on the other side toward many of the issues George cares most about and has worked to support for many years, including immigration reform, criminal justice reform and religious tolerance.”

The willingness of Soros to turn on the cash spigot full force to beat Trump is seen in Democratic finance circles as a very good sign for Clinton. Perhaps more than any other donor on the left, Soros is seen as having the potential to catalyze giving by others rich activists.

To be sure, other elite liberal donors are also stroking big checks, including San Francisco environmentalist Tom Steyer (who has donated $31 million in 2016, albeit almost entirely to a super PAC he controls), New York hedge funder Don Sussman ($13.2 million to various campaigns and committees) and media moguls Haim Saban and Fred Eychaner ($11.1 million each). But few have the bellwether effect of Soros.

The cumulative effect of the mobilization of the left’s richest benefactors has helped Clinton’s campaign and its allied outside groups mount a massive financial advantage over committees backing Trump, who is regarded with suspicion at best by the GOP donor class. That’s allowed Clinton and her allies to build a humming campaign machine that dwarfs Trump’s.

Soros has had a hand in funding many pieces of that.

Through the end of June, Soros had donated $7 million to a super PAC supporting Clinton called Priorities USA Action, according to FEC filings, making it the biggest recipient of his political largesse this cycle. And three Democratic operatives say he’s considering donating another $3 million to the group.

That spending, coupled with Soros’s inflammatory rhetoric

The spending made Soros a target of sometimes vicious personal attacks from conservative politicians and media outlets casting him as a puppet-master, a self-hating Jew, a communist or worse.

FEC records also show Soros gave $2 million to American Bridge 21st Century, an opposition research super PAC that has been targeting Trump and other Republican candidates, and $700,000 to an assortment of Democratic party committees, PACs and campaigns, including Clinton’s.

Soros has committed $5 million to a super PAC called Immigrant Voters Win that’s devoted to increasing turnout among low-propensity Hispanic voters in key swing states, though FEC records show he’d donated only $3 million through the end of June, the period covered by the most recent filings.

Soros has committed another $5 million to a non-profit devoted to fighting conservative efforts to restrict voting, according to the associate. That group, the Voting Rights Trust, is run partly by Clinton’s campaign lawyer Marc Elias. It’s registered under a section of the tax code that doesn’t require it to disclose its donors, meaning that Soros’s donations and those of other donors will never be formally publicly reported to the government, and also that it could be possible that some donations might be passed through from other groups.

Likewise, Vachon said Soros has committed or donated $2 million to a voter mobilization group called America Votes that doesn’t disclose its donors and another $1 million or so to a handful of state-based voter mobilization groups that are not required to disclose their donors.

And this month, according to Vachon, Soros donated $1.5 million each to Senate Majority PAC, a super PAC boosting Democratic Senate candidates, and to Planned Parenthood Votes, a super PAC that boosts candidates who support abortion rights, including Clinton.

The giving pattern and motivations seem similar to 2004, when Soros, motivated by a deep and abiding opposition to the Iraq War and other Bush administration policies, sprinkled $27 million around a handful of liberal groups boosting John Kerry’s unsuccessful challenge to Bush.

That spending, coupled with Soros’s inflammatory rhetoric — he compared the Bush administration’s rhetoric to that of the Nazis and described defeating the Bush as “a matter of life and death” — made him a target of sometimes vicious personal attacks from conservative politicians and media outlets casting him as a puppet-master, a self-hating Jew, a communist or worse.

Some allies say the public chastisement ate at Soros, as did the inability of his political spending spree to oust Bush, and his perhaps slightly ironic concerns that campaign finance laws allowed rich Americans like himself too much influence in politics.

And, after 2004, he dialed back his political giving, suggesting he might never again spend as heavily on politics, characterizing his involvement during the 2004 election as “an exception.”

Instead, he focused his philanthropic attention on his international foundations, which have donated more than $13 billion over the past three decades to non-profits that aim to defend human rights, shape the democratic process in Eastern Europe and expand access to healthcare and education in the U.S. and around the world.

And he played a formative role in the 2005 launch of a secretive club of major liberal donors called the Democracy Alliance. It sought to steer cash away from groups fighting short-term electoral battles and towards ones seeking to build intellectual infrastructure for long-term fights outside the Democratic Party, such as combating climate change, income inequality and the outsize role of big money in politics.

One liberal operative this week recalled asking someone close to Soros why the billionaire had reduced his spending on partisan politics.

“The answer was that he found it ‘odious’ for any one individual to throw too much political weight around through donations,” recalled the operative. “Maybe, in light of what's happened in the last few cycles, it seems less so, or he feels like he needs to help balance the outside-money scales a bit,” the operative added.

Additionally, though Soros backed Barack Obama over Clinton in the 2008 Democratic presidential primary, he quickly soured on the Democratic president, who he felt was insufficiently aggressive in pursuing liberal priorities. He expressed frustration with Obama during a private Democracy Alliance meeting in 2010, which some interpreted as a willingness to back a primary challenger in 2012. And though he backed Obama’s 2012 reelection campaign, that year he told a close Clinton ally that he regretted supporting Obama over her, and praised Clinton for giving him an open door to discuss policy, according to emails released late last year by the State Department.

"His giving has spiked because of Hillary. He really likes Hillary Clinton and he didn't like Obama as much” — Jordan Wood, End Citizens United national finance director

Soros “said he's been impressed that he can always call/meet with you on an issue of policy and said he hasn't met with the President ever (though I thought he had),” Clinton ally Neera Tanden wrote to the then-Secretary of State. Tanden continued that Soros “then said he regretted his decision in the primary — he likes to admit mistakes when he makes them and that was one of them. He then extolled his work with you from your time as First Lady on.”

Jordan Wood, the national finance director for a PAC called End Citizens United, on Tuesday suggested Soros’s giving may have slumped in recent years partly because of Obama. “With George, his giving has spiked because of Hillary. He really likes Hillary Clinton and he didn't like Obama as much,” said Wood, in an interview at a reception at a Center City bar for the campaign finance reform group Every Voice.

End Citizens United, which supports candidates including Clinton who pledge to push campaign finance reforms, this year received a $5,000 check from Soros, the maximum he could legally give to that group. He also has donated to Every Voice, as has his son Jonathan Soros, who attended Tuesday’s reception.

Jonathan Soros wouldn’t comment on his father’s increased political giving, but he pointed to George Soros’s recent writing about Trump, which includes one column in which Soros warned voters that it’s important to “resist the siren song of the likes of Donald Trump and Ted Cruz” if the U.S. is to effectively fight terrorism.